Social psychology is concerned with understanding individual behavior within a social context. It is a relatively young discipline, having been first developed in the early 20th century. At the time, many theorists in human behavior believed that behavior was governed by internal drives that were largely immutable. As an example. McDougall’s book An Introduction to Social Psychology (1908), emphasized innate and instinctive forces in human social behavior. These indwelling forces were not amenable to being changed by social contexts. In other words, there wasn’t a lot of room for an individual to have choices over how they behaved in social contexts, and there wasn’t much that involvement in those social situations could do to change a person’s innate drives.

Other psychologists disagreed and proposed a more flexible, two-way relationship between a person and their social contexts. A growing trend in social psychology saw human social behavior as more adaptive. By the 1920s, social psychology began to develop a perspective by focusing on how people behave within a social context and how social environments, in turn, affect individuals. Instead of behavior that was driven by innate drives, individual behaviors and those behaviors unique to social contexts came to be seen as reciprocal.

How each person thinks, feels and behaves in relation to social situations, as well as how specific features of social situations work to affect individual behaviors is at the heart of social psychology. A primary element of social psychology’s tenets is that it’s impossible for an individual not to be influenced by their social context. There is an ongoing two-way relationship between every person and their social contexts.

Note that social psychology developed in tandem with personality psychology and many of the founders and major figures of social psychology also studied the ways in which personality affects behavior. However, the two are separate sub-disciplines.

Although it’s challenging to identify only five key moments in the development of social psychology during the 20th century, consider the following as pivotal milestones in 20th-century social psychology.

Floyd Allport (1924) — Publication of Social Psychology

Social psychology’s power to explicate the individual experience of social contexts has grown in leaps and bounds over the last century largely owing to the rigor and reproducibility of experimental social psychology established by Floyd Allport. In fact, Allport is considered the father of experimental social psychology. His book Social Psychology was the first textbook to describe the principles of experimental research in relation to social psychology and thus set the stage for a future of quantifiable research in social psychology.

Leon Festinger (1957) — Cognitive Dissonance Theory

Festinger, along with Schacter and Black, developed the theory of cognitive dissonance, which states that people seek consistency among their beliefs, opinions, and actions. When there isn’t consistency, people experience dissonance. Dissonance causes discomfort, so people attempt to reconcile their beliefs, thoughts, and behaviors by changing either their behaviors or beliefs. People attempt to reconcile their behaviors and beliefs through a variety of ways, although typically behaviors remain constant and beliefs get changed in order to bring about consistency. Like Allport, Festinger also published an influential book, Research Methods in the Behavioral Sciences (1954), stressing the importance of good methodology in experimentation.

Albert Bandura (1963) — Social Learning Theory

Albert Bandura’s Social Learning Theory explicates the processes of learning through observing the behaviors of others and modeling behavior that’s been seen to be successful. Social Learning Theory develops and validates the concepts of observational learning and vicarious learning. Bandura explains human learning behavior as an ongoing two-way relationship between a person’s environment, their thoughts, and their behaviors. Bandura noted that children observed the consequences of other’s actions and modified their behavior. In contrast to strict behaviorism, Social Learning Theory established that children are affected by what happens to others as much as they are by the consequences of their own behaviors. The principles of observational learning, another important concept in social psychology, stem from Social Learning Theory.

Stanley Milgram (1963) – Milgram’s Shock Experiment and Compliance

In the early 1960s, Stanley Milgram, a psychologist at Yale University, became interested in investigating to what extremes people will go in order to obey or comply, with authority. The Nuremberg war crimes trials weren’t far in the past, and the idea that average people within the Nazi Third Reich could be easily compelled by authorities to commit atrocities was still new and disturbing. Milgram’s study involved telling the research subjects they were responsible for delivering electric shocks to another person if that person made errors on simple learning tasks. When the learner (a plant) got the answer wrong, the scientists (acting as the authority figures) told the subject they had to deliver an increasingly painful shock to the “learners,” although this didn’t really happen. Subjects were instructed to keep increasing the voltage every time the learner got an answer wrong. About 65 percent of the subjects escalated the voltage into lethal levels, although they questioned the scientists about the dangers. After prompting from the authority figures, the subjects continued increasing the shocks.

Milgram found that obedience to an authority tends to occur when an authority figure is present and people are uncertain about how to proceed. Both conditions must be present. People tend to offload responsibility for questionable actions onto those who present as either experts in knowledge, experience or established authority figures. As well, since the authority figure present was encouraging the subjects to deliver the shocks by emphasizing that the subjects had an imperative to do so, Milgram concluded that the subjects were displacing their own responsibility to the authority figures present in the experiments.

Zimbardo (1973) – Stanford Prison Experiment

Zimbardo’s prison experience established a landmark in the study of social roles and conformity. Zimbardo designed a study in which volunteers were randomly assigned either to the role of a guard or prisoner. They were then placed into a mock prison that superficially resembled a prison environment. Both groups degenerated into hostility, negativity and began to dehumanize one another. The Stanford Prison Experiment demonstrated the effect of social expectations on roles, even assumed roles.

Key moments in social psychology will continue to illuminate the experiences of individuals in varied social situations, which is critical to the ongoing health of society. Given the resurgence of old social ills like racism and xenophobia, these brilliant and enlightening moments can’t come soon enough.